(1) Under 18 years of age.

(2) A corporation not authorized to act as fiduciary in the Commonwealth.

(3) A person, other than an executor designated by name or description in the will, found by the register to be unfit to be entrusted with the administration of the estate.

(4) The nominee of any beneficiary, legatee or person having any interest whatsoever, when such beneficiary, legatee or person is a citizen or resident of any country outside the territorial limits or possessions of the United States, when it shall appear doubtful to the register that in the distribution of the estate any such person will have the actual benefit, use, enjoyment or control of the money or other property representing his share or interest therein.

(5) Charged, whether by indictment, information or otherwise, by the United States, the Commonwealth or any of the several states, with voluntary manslaughter or homicide, except homicide by vehicle, in connection with a decedent's death unless and until the charge is withdrawn, dismissed or a verdict of not guilty is returned.